Greenpeace activists dressed as flight attendants deliver a boarding card for a flight to Copenhagen to chief executive Donald Tsang.

Mr. Tsang has so far refused to commit to attending nor has he put forward a comprehensive climate policy and emissions reduction targets for Hong Kong.

The UN Copenhagen Climate Summit will open December 7.

Chinese Prime Minister Wen Jiabao and US President Barack Obama have already confirmed they would be attending the summit.

Danish Prime Minister Anders Fogh Rasmussen said more than 60 heads of state will attend the summit, including Germany, Britain, Spain, Japan, Australia and Brazil.

Mr. Tsang should also personally attend the meeting to show Hong Kong's commitment to stopping climate change, said Greenpeace climate campaigner Prentice Koo.

"The Copenhagen summit provides a top level opportunity for climate dialogue," said Mr. Koo. "Mr. Tsang should also join the conference as Hong Kong's top political official. Hong Kong is a developed city, it must not shirk its responsibility for solving the climate crisis. "

Although Secretary for the Environment Edward Yau has said he is going to Copenhagen, Greenpeace believes that the chief executive should attend because a comprehensive climate plan extends beyond the authority of the Environmental Bureau.

Mr. Tsang should first express his support of the need for developed nations to cut their greenhouse gas emissions by 25%-40% by 2020 over 1990 levels and to voice his support of developed countries funding climate adaptation measures in developing countries.